Soule and Oguri (1977) reported on a 1-year study conducted in Marina del Rey, although sampling actually continued for an additional 2 years. The informaton on the latter 2 years was drawn from unpublished data, and results for all 3 years (July 1976 to June 1979) of these zooplankton investigations are summarized here.
The zooplankton of Marina del Rey were dominated by copepods, which comprised over 98.5% of the zooplankton; cladocerans contributed 0.84%. Other less significant groups included larvaceans (0.34%), brachyura zoea (0.14%), cirripedia nauplii (0.12%), and fish eggs and larvae (0.04%). Among the copepods, Acartia spp. dominated with 97.4% of the total zooplankton. This genus was composed mainly of A. californiensis (97.4%) and A. tonsa (2.7%). Other numerically less important copepods included Paracalanus parvus (1.0%) and Corycaeus anglicus (0.1%). Four species of cladocerans occurred; Evadne nordmanni was the most common (0.29%) followed by Penilia avirostris (0.22%), Podon polyphemoides (0.21%), and Evadne spinifera (0.12%).
While zooplankton diversity was much less in Marina del Rey than that found in Los Angeles-Long Beach Harbors, the areal distribution of A. tonsa and A.californiensis followed a similar pattern. A. californiensis was most abundant in the inner main channel and slips, while A. tonsa was found primarily in the entrance channel and mouth of the harbor.
Fundamental Ecosystem of Ocean Water in Marina Del Rey Yacht Harbor
Edited and Compiled by
Roy van de Hoek
Marine Biologist & Geographer
December 21, 2002
A little science to understand why fish, seals, jellies, pelicans, cormorants, grebes, herons and egrets like to spend time at Marina del Rey can lead to some revisionist thinking about the importance of the yacht harbor as a marine sanctuary and a unique ecosystem of southern California.
The excerpt above comes from the book entitled: Ecology of the Southern California Bight. In chapter 6, entitled "Zooplankton" (pages 266-303) and written by John K. Dawson and Richard E. Pieper, the authors wrote 37 pages about zooplankton all around southern California, with this 2 page (270-271) essay about Marina del Rey. The book is not too old, published 10 years ago, in 1993, by University of California Press, and co-edited by three marine biologists: Murray Dailey, Donald Reish, and Jack Anderson. By the way, Dawson and Pieper were affiliated with USC in Los Angeles.
While doing research on herons of Marina del Rey, I stumbled onto this section of a fabulous book, Marine Biology of the Southern California Bight, that discussed the zooplankton of Marina del Rey Yacht Harbor. I immediately recognized this section as an important document to be included in the web page on the anthology of nature of Marina del Rey. It is in that light, for education, awareness, and science that I have presented it on this web page. Enjoy it even if it may be a little technical. Remember to note that these small plankton are the basis of food for small fish and marine invertebrates, which are then in turn eaten by bigger fish, herons, egrets, and seals. Knowing this small bit of information will then allow you to appreciate plankton in a new light. If there is no plankton, there are no fish, whales, seals, pelicans and myriads of other ocean life that depend of the plankton. My brief synthesis indicates that the species of zooplankton identified are the same species also found in Newport Bay and Long Beach-San Pedro Harbor.